The present invention relates to an apparatus for determining the foam formation of crude petroleum during blowing or distilling off of liquids which are dissolved or finely distributed in the crude petroleum and which boil under testing conditions.
As a rule, crude petroleum is under considerable pressure when stored in deposits. This high pressure causes hydrocarbons to be dissolved in the crude petroleum. Since the pressure of the crude petroleum is reduced during its production, the dissolved hydrocarbons escape from the crude petroleum. During blowing off of the low-boiling hydrocarbons, the crude petroleum foams more or less intensely. The stability and quantity of the foam depend on the place of origin of the crude petroleum, its viscosity and particularly the quantity of low-boiling hydrocarbons contained in the crude petroleum. This foam formation frequently creates considerable problems during production and storage of crude petroleum.
In order to prevent or reduce the formation of foam and to decrease the stability of the foam, it is known to add chemicals to the crude petroleum as it is produced.
Even though the practical usefulness of an anti-foaming agent can be actually determined only during its use at the production site, it is desirable to make a preliminary selection under laboratory conditions of compounds which are expected to be suitable. For this purpose, it necessary to simulate the conditions of foam generation and elimination as close to the actual conditions as possible.
A method for determining the effectiveness of anti-foaming agents for crude petroleum is known. In accordance with this method, foam is generated by conducting air or natural gas through a sample of crude petroleum. After shutting off the gas supply, the foam level is measured in certain time intervals and plotted in a diagram over time. The area below the curve represents a measure for the lifetime of the foam. When tests are performed, the lifetime of the foam of an untreated sample of crude petroleum is compared to the lifetimes of foams in samples containing various anti-foaming agents and samples containing different quantities of anti-foaming agents. A decreasing lifetime of the foam indicates an increased efficiency of the anti-foaming agent.
In the above-described method, the criterion of the measurement is the period of time it takes for the already formed foam to disintegrate. However, during actual production, new foam is continuously formed during blowing off of liquids, so that it is important to evaluate the foam formation and to find ways to prevent the generation of foam.
It is, therefore, an object of the invention to provide an apparatus for accurately simulating the actual conditions under which foam is generated and prevented or eliminated.